• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.11
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• pp.617-623
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• 2013

This study is to draw thermal property data during long-term aging, by testing the thermal conductivity of building insulation materials in Korea. The thermal resistance of extruded insulation within 3 days from manufacture performed well over the KS Standard. After 50 to 110 days, however, the thermal performance had deteriorated to the level of the KS standard. Eventually, after 4,000 days, the insulation performance had deteriorated to about 25.4~41.8% of the initial performance. Therefore, this research will be utilized as a reference for thermal properties during long-term aging, in order to improve standards and regulations related to building insulation materials.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.555-555
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• 2009

A web GIS based database system of thermophysical property of rocks in Korea is under construction. Rock samples were randomly collected over the whole country and sample spacings were generally 1 to 10 km. Thermal diffusivity, spedific heat, thermal conductivity, specific heat, density and porosity were measured on a collection of 1,560 rock samples in the laboratory. The sampled rocks were classified into igneous, metamorphic and sedimentary rock types and the variables were statistically studied. The thermal conductivity were compared with thermal diffusivity, porosity and dry density to define any correlations and the distribution of thermal conductivity is characterized by the geostatistical analysis. The optimal mapping of thermal conductivity is very useful as a practical design component for any geothermal systems.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.429-433
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• 2007

Cement mortar and concrete can be used as grouts but problems regarding shrinkage and the discord of coefficients of thermal expansion between grouts and HDPE pipes has to be solved. Thermal conductivities of wet condition two times larger than those of dry condition, except for pure cement mortar. The addition of sand into the cement grouts greatly increases the thermal conductivity. The addition of bentonite into the cement grouts reduces thermal conductivity thus reducing the density. Bentonite grouting must be used only below the groundwater table since bentonite grouts possesses high shrinkage property in dry condition. The addition of sand prevents the shrinkage of bentonite grouts. Bentonite manufactured in Korea can be used since they possess similar thermal conductivities with imported products. The addition of sand into the bentonite grouts greatly increases the thermal conductivity.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.11a
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• pp.277-280
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.72-72
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• 1992

• Proceedings of the Korean Fiber Society Conference
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• 1994.04a
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• pp.101-101
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• 1994

• Polymer(Korea)
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• v.38 no.5
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• pp.632-639
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• 2014

2,7-Dihydroxynaphthalene bis(trimellitate anhydride) (2,7-TA) was synthesized from trimellitic anhydride chloride and 2,7-dihydroxynaphthalene. Copolyimides (Co-PI) containing ester group were synthesized from 2,7-TA, pxylylenediamine, and 2,2'-bis(trifluoromethyl)benzidine (TFB). The Co-PI films were obtained from poly(amic acid) by solution casting through thermal imidization on a glass plate. The thermal property, gas permeation, and optical transparency of the Co-PI films with various TFB monomer contents were investigated. These Co-PIs could be solution-cast into a flexible and tough film. The cast Co-PI films exhibited high optical transparency with a cut-off wavelength of 370~395 nm in UV-vis. absorption and a low yellow index value of 3.55~7.63. The thermal property of Co-PI films increased linearly with increasing TFB content. However, the oxygen permeation and optical transparency of the Co-PI films was found to worsen with increasing TFB content.

• 한국전기화학회:학술대회논문집
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• 2001.11a
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• pp.145-161
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• 2001

Novel characterization of thermal properties of a battery has been introduced by defining its frequency-dependent thermal impedance function. Thermal impedance function can be approximated as a thermal impedance spectrum by analyzing experimental temperature transient which is related to the thermal impedance function through Laplace transformation. In order to obtain temperature transient, a process has been devised to generate external heat pulse with heating wire and to measure the response of battery. This process is used to study several commercial Li-ion batteries of cylindrical type. The thermal impedance measurements have been performed using potentionstat/galvanostate controlled digital signal processor, which is more commonly available than flow-meter usually applied for thermal property measurements. Thermal impedance spectra obtained for batteries produced by different manufactures are found to differ considerably. Comparison of spectra at different states of charge indicates independence of thermal impedance on charging state of battery. It is shown that thermal impedance spectrum can be used to obtain simultaneously thermal capacity and thermal conductivity of battery by non-linear complex least-square fit of the spectrum to thermal impedance model. Obtained data is used to simulate a response of the battery to internal heating during discharge. It is found that temperature inside the battery is by one-third larger that on its surface. This observation has to be considered to prevent damage by overheating.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1344-1347
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• 2004

Recently, Study on measuring property of a micro thin film(nm ～ hundreds of ) under Thermal Mechanical loading. In this work, We perform tensile test at high temperature(1200 ) to investigate mechanical properties of alumina TGO formed under Thermal Barrier Coating. We used Digital Image Correlation method for measuring displacement, and We presented a method of tensile test for thin film at high temperature.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3249-3253
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• 2014

A novel triazole-functionalized phenolic resin was developed, and its thermal and flame-retardant properties were investigated. The triazole group was incorporated as a pendant unit on the phenolic resin via copper-mediated click chemistry between propargylated phenolic resin and benzyl azide. The newly-developed triazole-functionalized phenolic resin showed higher thermal stability and char yield, together with a reduced total heat release (THR), than the non-functionalized bare phenolic resin, indicating enhanced flame retardancy for the triazole-functionalized phenolic resin.